{
   Copyright 2005-2012 Sandy Barbour and Ben Supnik
   
   All rights reserved.  See license.txt for usage.
   
   X-Plane SDK Version: 2.1.1                                                  
}

UNIT XPLMGraphics;
INTERFACE
{
   Graphics routines for X-Plane and OpenGL. 
   
   A few notes on coordinate systems: 
   
   X-Plane uses three kinds of coordinates.  Global coordinates are specified 
   as latitude, longitude and elevation.  This coordinate system never changes 
   but is not very precise.   
   
   OpenGL (or 'local') coordinates are cartesian and shift with the plane.  
   They offer more precision and are used for 3-d OpenGL drawing.  The X axis 
   is aligned east-west with positive X meaning east.  The Y axis is aligned 
   straight up and down at the point 0,0,0 (but since the earth is round it is 
   not truly straight up and down at other points).  The Z axis is aligned 
   north-south at 0, 0, 0 with positive Z pointing south (but since the earth 
   is round it isn't exactly north-south as you move east or west of 0, 0, 0). 
   One unit is one meter and the point 0,0,0 is on the surface of the  earth 
   at sea level for some latitude and longitude picked by the sim such that 
   the  user's aircraft is reasonably nearby. 
   
   Cockpit coordinates are 2d, with the X axis horizontal and the Y axis 
   vertical. The point 0,0 is the bottom left and 1024,768 is the upper right 
   of the screen. This is true no matter what resolution the user's monitor is 
   in; when running in higher resolution, graphics will be scaled. 
   
   Use X-Plane's routines to convert between global and local coordinates.  Do 
   not attempt to do this conversion yourself; the precise 'roundness' of 
   X-Plane's  physics model may not match your own, and (to make things 
   weirder) the user can potentially customize the physics of the current 
   planet.                                                                     
}

USES   XPLMDefs;
   {$A4}
{$IFDEF MSWINDOWS}
   {$DEFINE DELPHI}
{$ENDIF}
{___________________________________________________________________________
 * X-PLANE GRAPHICS
 ___________________________________________________________________________}
{
   These routines allow you to use OpenGL with X-Plane.                        
}



   {
    XPLMTextureID
    
    XPLM Texture IDs name well-known textures in the sim for you to use. This 
    allows you to recycle textures from X-Plane, saving VRAM.                   
   }
TYPE
   XPLMTextureID = (
     { The bitmap that contains window outlines, button outlines, fonts, etc.      }
      xplm_Tex_GeneralInterface                = 0
 
     { The exterior paint for the user's aircraft (daytime).                       }
     ,xplm_Tex_AircraftPaint                   = 1
 
     { The exterior light map for the user's aircraft.                             }
     ,xplm_Tex_AircraftLiteMap                 = 2
 
   );
   PXPLMTextureID = ^XPLMTextureID;

   {
    XPLMSetGraphicsState
    
    XPLMSetGraphicsState changes OpenGL's graphics state in a number of ways: 
    
    inEnableFog - enables or disables fog, equivalent to: glEnable(GL_FOG);
    
    inNumberTexUnits - enables or disables a number of multitexturing units. If 
    the number is 0, 2d texturing is disabled entirely, as in 
    glDisable(GL_TEXTURE_2D);  Otherwise, 2d texturing is enabled, and  a 
    number of multitexturing units are enabled sequentially, starting  with 
    unit 0, e.g. glActiveTextureARB(GL_TEXTURE0_ARB);  glEnable 
    (GL_TEXTURE_2D);
    
    inEnableLighting - enables or disables OpenGL lighting, e.g.  
    glEnable(GL_LIGHTING); glEnable(GL_LIGHT0);
    
    inEnableAlphaTesting - enables or disables the alpha test per pixel, e.g. 
    glEnable(GL_ALPHA_TEST);
    
    inEnableAlphaBlending - enables or disables alpha blending per pixel, e.g. 
    glEnable(GL_BLEND);
    
    inEnableDepthTesting - enables per pixel depth testing, as in  
    glEnable(GL_DEPTH_TEST);
    
    inEnableDepthWriting - enables writing back of depth information to the 
    depth bufffer, as in glDepthMask(GL_TRUE); 
    
    The purpose of this function is to change OpenGL state while keeping 
    X-Plane aware of the state changes; this keeps X-Plane from getting 
    surprised by OGL state changes, and prevents X-Plane and plug-ins from 
    having to set all state before all draws; XPLMSetGraphicsState internally 
    skips calls to change state that is already properly enabled. 
    
    X-Plane does not have a 'default' OGL state to plug-ins; plug-ins should  
    totally set OGL state before drawing.  Use XPLMSetGraphicsState instead of 
    any of the above OpenGL calls. 
    
    WARNING: Any routine that performs drawing (e.g. XPLMDrawString or widget 
    code) may change X-Plane's state.  Always set state before drawing after 
    unknown code has executed.                                                  
   }
   PROCEDURE XPLMSetGraphicsState(
                                        inEnableFog         : integer;    
                                        inNumberTexUnits    : integer;    
                                        inEnableLighting    : integer;    
                                        inEnableAlphaTesting: integer;    
                                        inEnableAlphaBlending: integer;    
                                        inEnableDepthTesting: integer;    
                                        inEnableDepthWriting: integer);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMBindTexture2d
    
    XPLMBindTexture2d changes what texture is bound to the 2d texturing target. 
    This routine caches the current 2d texture across all texturing units in 
    the sim and plug-ins, preventing extraneous binding.  For example, consider 
    several plug-ins running in series; if they all use the 'general interface' 
    bitmap to do UI, calling this function will skip the rebinding of the 
    general interface texture on all but the first plug-in, which can provide 
    better frame rate son some graphics cards. 
    
    inTextureID is the ID of the texture object to bind; inTextureUnit is a 
    zero-based  texture unit (e.g. 0 for the first one), up to a maximum of 4 
    units.  (This number may increase in future versions of x-plane.) 
    
    Use this routine instead of glBindTexture(GL_TEXTURE_2D, ....);             
   }
   PROCEDURE XPLMBindTexture2d(
                                        inTextureNum        : integer;    
                                        inTextureUnit       : integer);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMGenerateTextureNumbers
    
    This routine generates unused texture numbers that a plug-in can use to 
    safely bind textures. Use this routine instead of glGenTextures; 
    glGenTextures will allocate texture numbers in ranges that X-Plane reserves 
    for its own use but does not always use; for example, it might provide an 
    ID within the range of textures reserved for terrain...loading a new .env 
    file as the plane flies might then cause X-Plane to use this texture ID.  
    X-Plane will then  overwrite the plug-ins texture.  This routine returns 
    texture IDs that are out of X-Plane's usage range.                          
   }
   PROCEDURE XPLMGenerateTextureNumbers(
                                        outTextureIDs       : Pinteger;    
                                        inCount             : integer);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMGetTexture
    
    XPLMGetTexture returns the OpenGL texture enumeration of an X-Plane texture 
    based on a  generic identifying code.  For example, you can get the texture 
    for X-Plane's UI bitmaps.  This allows you to build new gauges that take 
    advantage of x-plane's textures, for smooth artwork integration and also 
    saving texture  memory.  Note that the texture might not be loaded yet, 
    depending on what the  plane's panel contains. 
    
    OPEN ISSUE: We really need a way to make sure X-Plane loads this texture if 
    it isn't around, or at least a way to find out whether it is loaded or not. 
   }
   FUNCTION XPLMGetTexture(
                                        inTexture           : XPLMTextureID) : integer;    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMWorldToLocal
    
    This routine translates coordinates from latitude, longitude, and altitude 
    to local scene coordinates. Latitude and longitude are in decimal degrees, 
    and altitude is in meters MSL (mean sea level).  The XYZ coordinates are in 
    meters in the local OpenGL coordinate system.                               
   }
   PROCEDURE XPLMWorldToLocal(
                                        inLatitude          : real;    
                                        inLongitude         : real;    
                                        inAltitude          : real;    
                                        outX                : Preal;    
                                        outY                : Preal;    
                                        outZ                : Preal);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMLocalToWorld
    
    This routine translates a local coordinate triplet back into latitude, 
    longitude, and altitude.  Latitude and longitude are in decimal degrees, 
    and altitude is in meters MSL (mean sea level).  The XYZ coordinates are in 
    meters in the local OpenGL coordinate system. 
    
    NOTE: world coordinates are less precise than local coordinates; you should 
    try to avoid round tripping from local to world and back.                   
   }
   PROCEDURE XPLMLocalToWorld(
                                        inX                 : real;    
                                        inY                 : real;    
                                        inZ                 : real;    
                                        outLatitude         : Preal;    
                                        outLongitude        : Preal;    
                                        outAltitude         : Preal);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMDrawTranslucentDarkBox
    
    This routine draws a translucent dark box, partially obscuring parts of the 
    screen but making text easy to read.  This is the same graphics primitive 
    used by X-Plane to show text files and ATC info.                            
   }
   PROCEDURE XPLMDrawTranslucentDarkBox(
                                        inLeft              : integer;    
                                        inTop               : integer;    
                                        inRight             : integer;    
                                        inBottom            : integer);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

{___________________________________________________________________________
 * X-PLANE TEXT
 ___________________________________________________________________________}
{
                                                                               
}



   {
    XPLMFontID
    
    X-Plane features some fixed-character fonts.  Each font may have its own 
    metrics. 
    
    WARNING: Some of these fonts are no longer supported or may have changed 
    geometries. For maximum copmatibility, see the comments below. 
    
    Note: X-Plane 7 supports proportional-spaced fonts.  Since no measuring 
    routine is available yet, the SDK will normally draw using a fixed-width 
    font.  You can use a dataref to enable proportional font drawing on XP7 if 
    you want to.                                                                
   }
TYPE
   XPLMFontID = (
     { Mono-spaced font for user interface.  Available in all versions of the SDK. }
      xplmFont_Basic                           = 0
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_Menus                           = 1
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_Metal                           = 2
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_Led                             = 3
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_LedWide                         = 4
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_PanelHUD                        = 5
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_PanelEFIS                       = 6
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_PanelGPS                        = 7
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_RadiosGA                        = 8
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_RadiosBC                        = 9
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_RadiosHM                        = 10
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_RadiosGANarrow                  = 11
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_RadiosBCNarrow                  = 12
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_RadiosHMNarrow                  = 13
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_Timer                           = 14
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_FullRound                       = 15
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_SmallRound                      = 16
 
     { Deprecated, do not use.                                                     }
     ,xplmFont_Menus_Localized                 = 17
 
{$IFDEF XPLM200}
     { Proportional UI font.                                                       }
     ,xplmFont_Proportional                    = 18
{$ENDIF}
 
   );
   PXPLMFontID = ^XPLMFontID;

   {
    XPLMDrawString
    
    This routine draws a NULL termianted string in a given font.  Pass in the 
    lower left pixel that the character is to be drawn onto.  Also pass the 
    character and font ID. This function returns the x offset plus the width of 
    all drawn characters. The color to draw in is specified as a pointer to an 
    array of three floating point colors, representing RGB intensities from 0.0 
    to 1.0.                                                                     
   }
   PROCEDURE XPLMDrawString(
                                        inColorRGB          : Psingle;    
                                        inXOffset           : integer;    
                                        inYOffset           : integer;    
                                        inChar              : Pchar;    
                                        inWordWrapWidth     : Pinteger;    { Can be nil }
                                        inFontID            : XPLMFontID);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMDrawNumber
    
    This routine draws a number similar to the digit editing fields in 
    PlaneMaker and data output display in X-Plane.  Pass in a color, a 
    position, a floating point value, and formatting info.  Specify how many 
    integer and how many decimal digits to show and  whether to show a sign, as 
    well as a character set. This routine returns the xOffset plus width of the 
    string drawn.                                                               
   }
   PROCEDURE XPLMDrawNumber(
                                        inColorRGB          : Psingle;    
                                        inXOffset           : integer;    
                                        inYOffset           : integer;    
                                        inValue             : real;    
                                        inDigits            : integer;    
                                        inDecimals          : integer;    
                                        inShowSign          : integer;    
                                        inFontID            : XPLMFontID);    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

   {
    XPLMGetFontDimensions
    
    This routine returns the width and height of a character in a given font. 
    It also tells you if the font only supports numeric digits.  Pass NULL if 
    you don't need a given field.  Note that for a proportional font the width 
    will be an arbitrary, hopefully average width.                              
   }
   PROCEDURE XPLMGetFontDimensions(
                                        inFontID            : XPLMFontID;    
                                        outCharWidth        : Pinteger;    { Can be nil }
                                        outCharHeight       : Pinteger;    { Can be nil }
                                        outDigitsOnly       : Pinteger);    { Can be nil }
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}

{$IFDEF XPLM200}
   {
    XPLMMeasureString
    
    This routine returns the width in pixels of a string using a given font.  
    The string is passed as a pointer plus length (and does not need to be null 
    terminated); this is used to allow for measuring substrings. The return 
    value is floating point; it is possible that future font drawing may allow 
    for fractional pixels.                                                      
   }
   FUNCTION XPLMMeasureString(
                                        inFontID            : XPLMFontID;    
                                        inChar              : Pchar;    
                                        inNumChars          : integer) : single;    
{$IFDEF DELPHI}
                                       cdecl; external 'XPLM.DLL';
{$ELSE}
                                       cdecl; external '';
{$ENDIF}
{$ENDIF}

IMPLEMENTATION
END.
